Watching her son parade with rows of fellow troops, she notices he is on his left foot when they are all on the right.

“Why are they out of step?” she asks.

So it is with Barack Obama. The nation is turning against him, yet he shouts to the heavens that he is right and the country is wrong.

Mothers can get away with that sort of thing. Presidents and their parties get shellacked.

The Quinnipiac poll showing that Obama is now considered the worst president since World War II offers him no silver lining. There were 12 choices and the voting wasn’t close — he got the highest “worst” vote, 33 percent, with George W. Bush the next worst, at 28 percent.

Jimmy Carter, routinely mocked as a disaster, drew only 8 percent. Even Richard Nixon did better, seen as the bottom of the barrel by only 13 percent of those surveyed. And we know how Nixon’s tenure ended.

Too bad America didn’t come to its senses sooner. Indeed, the Q poll shows a huge amount of buyers’ remorse, with 45 percent saying Mitt Romney would have been a better president, while only 38 percent think Obama was the right choice in 2012. Mulligan, anyone?

Let me be clear: Obama is flirting with disaster. This and other polls show he is losing ground with every group, including African-Americans.

Most important, clear majorities no longer trust him and no longer believe he is capable of leading the country.

His policies, especially ObamaCare, were never popular, but the accumulation of his failures has eroded his ability to defy political gravity.

That’s what happens when you get caught in too many lies and broken promises about fixing the economy. And don’t underestimate the impact of the global chaos on Americans’ sour mood.

Losing the consent of the governed is a profound event, and there is no easy path back to public grace. The one certainty is that Obama’s angry defiance will dig him a deeper hole.

Let me be clear: Obama is flirting with disaster … His policies, especially ObamaCare, were never popular, but the accumulation of his failures has eroded his ability to defy political gravity.

His taunting of Republicans and critics in campaign-style events reinforces doubts about his fitness. Absorbed with self-pity and fixated on finding blame, he gives the impression of someone who never considers the possibility he might be part of the problem.

“So sue me,” he said at one point about GOP claims that he is exceeding lawful authority. “It’s not crazy. It’s not socialism. You know, it’s not, you know, the imperial presidency.”

House Speaker John Boehner, who does intend to sue Obama, had a telling response about why his caucus would not pass an immigration bill. “The American people and their elected officials don’t trust [Obama] to enforce the law,” he said.

Supreme Court decisions voiding the president’s overreach are one example, and the crisis on the southern border is another. By trying to put pressure on Republicans, and to score votes among liberals, Obama selectively enforced only parts of the immigration law — and advertised his desire to exempt those who came here illegally as children.

Word quickly spread in Latin and Central America that if young people got across, they wouldn’t be sent back. And so they came, by the tens of thousands. Where did they get that message if not from the president?

While it’s clear Obama will not listen to the public, there is still an outside chance that senior members of his party can persuade him to change course. Their argument would be a simple one: This isn’t working, and if you continue, Republicans will take the Senate and might well impeach you.